A new government investigation suggests that the Transportation Security Administration is not collecting enough detailed information to know if its bomb dogs are well trained and capable of finding bombs at the nation's airports, and includes secret video that shows the dogs failing tests to detect explosives.

TSA has been testing bomb dogs in Miami and Oklahoma City and will be testing them at Dulles airport, outside Washington, D.C., this month.

A GAO report released this week, however, says that the passenger-screening canines have not been adequately tested, and included secret video shot over the past year that showed the dogs failing to detect explosives properly at the test airports.

The report also said that "TSA could have benefited from completing operational assessments of PSCs before deploying them on a nationwide basis to determine whether they are an effective method of screening passengers in the U.S. airport environment."

In a statement, the TSA said it "acknowledges the need to further examine the data collected over a longer term. To that end, the National Canine Program (NCP) will reestablish annual comprehensive assessments. Beginning in March 2013, TSA plans to expand the Canine Website to improve functionality and reporting capabilities addressing a GAO recommendation."

It also said that this month it would complete effectiveness assessments at Miami, Oklahoma City and Dulles airports, and that it would identify the proper places for the dogs to be deployed at 120 airports by the end of fiscal 2013.

The cost of keeping bomb-sniffing dogs on the government's payroll has almost doubled in the past two years, from $52 million to more than $100 million. Each TSA dog team costs the taxpayers $164,000 dollars a year.

"They want to do the right thing," aviation expert Jeff Price told ABC News, "but the homework hasn't been done. A lot of money gets spent before they know something works."